Disable shadow copy when running from ZIP

When running from ZIP/read only mode, we can safely skip the shadow copy process, which does impact startup time.

Opening this to track the work to have that disabled in those cases.

Start by locating the shadow copy process and the code that detects ZIP or read-only execution in the host/runtime. Verify the startup path skips shadow copying only in those cases, then confirm that normal execution still performs it and that startup time is improved.

Written by the indexing model from the issue text.